/Engine/Plugins/FX/Niagara/Source/Niagara/Public/NiagaraComponent.h
Gets the fixed bounds for the system instance. This will return the user set fixed bounds if set, or the systems fixed bounds if set. Note: The returned box may be invalid if no fixed bounds exist
[UFUNCTION](Programming/UnrealArchitecture/Reference/Functions)(BlueprintCallable, Category=Niagara) FBox GetSystemFixedBounds() const